United States Navy Mark 12 Special Purpose Rifle (Mk 12 SPR)

History of the US Navy Mark 12 Special Rifle (Mk 12 SPR)

The Mark 12 Special Purpose Rifle (Mk 12 SPR) entered service with the US Special Forces in 2002 and has been in continuous service ever since. The weapon has seen prominent use in theater operations in Afghanistan and Iraq, often in the hands of highly trained specialists from the U.S.

Army and Navy. In fact, the main operator of the SPR is the US Navy SEALs, which requires the SPR to be a reliable, efficient and powerful weapon system.

Designed for use by the Naval Surface Warfare Center Crane Division (NSA Crane), the Mk 12 is primarily based on how the AR-15/M16 style rifle works, with some notable external additions and modifications.

The Mk 12 grew out of a joint U.S. Army and Navy need for a compact semi-automatic sniper system. Several prototypes were considered and then extensively tested, culminating in the "Mk 12" form. Like the AR-15 and M16, the Mk 12 is housed in a 5.56x45mm NATO, but the cartridge itself is specifically designed for the Mk 12's semi-automatic pneumatic rotary bolt action system.

Fed by a 20- or 30-round detachable magazine, the weapon more or less retains the form and function of the AR-15/M16 on the battlefield. It is said to have an effective range of 600 yards and a muzzle velocity of nearly 3,050 feet per second.

The pistol grip features an ergonomic groove for a firm grip, while the trigger is in an integrated guard. The magazine slot is usually directly in front of the trigger unit.

The front fender consists of a perforated tubular handguard to which an accessory rail section is attached on the underside of the front - this allows stable shooting with a collapsible bipod. The upper and front end of the receiver also has a rail system for using tactical accessories and optics as needed. The shoulder rest extends from a collapsible tubular frame to help the operator achieve a stable four-point firing position (hands, bipod and shoulder rest) for maximum range accuracy.

The barrel protrudes only a short distance from the front end and is closed by a single-wall muzzle brake. The barrel is 18 inches long, while the overall length of the SPR weapon is 37.5 inches. The fully loaded rifle weighs 10 pounds, slightly heavier than the original M16.

By comparison, the M16 is 39.5 inches long and has a barrel length of 20 inches.

There are several notable iterations of the Mk 12: "Mk 12 Mod 0" for Army Special Forces and "Mk 12 Mod 1" for Navy Special Forces. The official "long name" for the rifle is "US Navy Mark 12 Mod 0/1 Special Rifle".

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